1. Field of the Invention
The present invention relates to a tumor therapy that includes the injection of immature dendritic cells and adjuvant directly into the patient's (a human or an animal) tumor tissue, which presents antigenicity as a vaccine antigen at the injection sight. Conjugation of these elements within the tumor tissue rapidly induce and activate the patient's immune system to dramatically reduce and/or eliminate tumor cells. Most adjuvants, which augment the immune response, can be directly injected with immature dendritic cells to the tumor tissue to achieve the reduction or elimination of tumor tissues.
2. Description of the Prior Art
Immunological adjuvants are used in combination with vaccines to augment the immune response to the antigen. One way in which immunological adjuvants function is by attracting macrophages to the antigen, so that the macrophages can present the antigen to the regional lymph nodes and initiate an effective antigenic response. Adjuvants may also act as carriers themselves for the antigen, or may influence the immune response by other mechanisms such as depot effect, cytokine induction, complement activation, recruiting of different cell populations of the immunological system, antigen delivery to different antigen presenting cells, regulation of the expression of HLA class I or class II molecules and the stimulation to produce different antibody subtypes. Many of the newer vaccines are only weakly immunogenic and thus require the presence of adjuvants.
Materials having adjuvant activity are well known. Alum (Al(OH)3), and similar aluminum gels are adjuvants licensed for human use. The adjuvant activity of alum was first discovered in 1926 by Glenny (Chemistry and Industry, Jun. 15, 1926; J. Path. Bacteriol, 34, 267). Aluminum hydroxide and aluminum phosphate (collectively commonly referred to as alum) are routinely used as adjuvants in human and veterinary vaccines. The efficacy of alum in increasing antibody responses to diphtheria and tetanus toxoids is well established and, more recently, a HBsAg vaccine has been adjuvanted with alum.
One line of research in the development of adjuvants has been directed to the study of dendritic cells. Dendritic cells (DC) are professional antigen presenting cells (APC) that have the unique capacity to initiate primary immune responses in vivo and in vitro. They are derived from myeloid (DC1) or lymphoid (DC2) precursors and are distributed in their immature form throughout the body in tissues that commonly encounter environmental pathogens (skin, mucus membranes, gut epithelia, etc.). Whereas DC1 and DC2 comprise a small percentage of the total number of mononuclear cells in the peripheral circulation, DC1 precursors in the form of CD14+/CD11c+/HLA-DR+ monocytes are relatively abundant, constituting about 10% to 15% of mononuclear blood cells.
Immature DC express a host of surface structures that are involved in antigen acquisition, DC activation/maturation, and antigen presentation. Once DC encounter antigen, they undergo a maturation process characterized by the up-regulation of HLA class I and II molecules as well as co-stimulatory molecules and interact with cognate receptors on T and B lymphocytes, resulting in the generation of antigen specific cellular and humoral immune responses.
DC are considered to be the primary APC in the immune system. The ability to isolate these cells and/or their precursors and to study them in vitro has added considerable dimension to knowledge of their role in innate and acquired immunity. The classic means of generating human DC in vitro is to isolate and enrich CD14+-monocytes from peripheral blood and culture them for various periods of time in GM-CSF and IL-4 followed by final maturation with a number of cytokines, including IL-2, IL-6, IL-7, IL-13, IL-15, TNFα, IL-10, or with various other agents including lipopolysaccharides, PGE2, type 1 interferons, or double-stranded RNA.
Numerous investigators have shown that these in vitro generated monocyte-derived DC are potent antigen presenting cells (APC) capable of initiating primary and recall antigen-specific CD4+ and CD8+ T cell responses. Recent in vitro studies have generated a rather extensive body of information regarding the biology of DC1 and shed light on the processes whereby antigen specific immune responses are generated in vivo. In the peripheral tissues, immature DC acquire antigenic materials in the context of danger signals initiating a complex cytokine/chemokine milieu that is generated by DC and other cell types in the vicinity.
Soluble mediators produced by DC may act in an autocrine or paracrine fashion. T cells produce additional cytokines and chemokines following interaction with antigen armed DC, as do other immune cells that are activated by the cytokines released. This complex network of interactions may in turn create an environment that promotes the generation of DC from their monocyte precursors.
It is thought that those adjuvants which promote that maturation of dendritic cells, when administered in combination with a vaccine antigen, will result in more antigen presenting cells presenting the vaccine antigen to T lymphocytes and B cells, thus bolstering the immune response to the vaccine antigen. However, isolation of the most effective vaccine antigen has been extremely difficult since antigenicity of APC has always been subject to its evolution with antigenic drift and/or shift, and therefore many of the newer vaccines are only weakly immunogenic even though dendritic cells and adjuvant are present. The most effective vaccine antigen against the live tumor cells should be used with dendritic cells and adjuvant during a course of treatment to promote and to induce a rather strong immunogenicity.